Study on Mechanism of Electroactive Microorganisms Response to 2,4-Dcp

Abstract

In electroactive microorganisms, voltage drop caused by toxic substances is linked to the metabolic activity. This study found that microorganisms attaching to carbon felt contributed directly to electricity generation. After 2,4-DCP administration, the trend of voltage change mainly comprised four stages, and the gradual shedding of the attached microorganisms was consistent with the decrease in voltage, indicating a significant decrease in the electroactivity of microorganisms in the presence of 2,4-DCP. Adenosine triphosphate (ATP), nicotinamide adenine dinucleotide (NAD(H)), and dehydrogenases (DHA) activities decreased by 90%, 96%, and 19%, respectively. This was a major reason for the rapid decline in the output electrical signal. In addition to the changes in antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) activities increased by 1.5 times and 60 times respectively, in the initial voltage drop stage. The effect of GSH-Px was not significant. The ability to resist damage caused by toxic substances was mainly reflected in the early stage. Lipid peroxidation during the initial voltage drop stage was the primary reason for the rapid decline in the electrical signal. After being exposed to toxic substances, microbial signal transmission was reduced, as the microorganisms diverted resources towards cell proliferation.

Keywords: Microbial fuel cell (MFC), toxicity, metabolic activity, lipid peroxidation.